RFID tag with twin IC design for generating omnidirectional radiation pattern without null

Abstract

A RFID tag that includes a first RF chip, a second RF chip, a first wiring and a second wiring is provided. The first RF chip and the second RF chip are adjacent and connected to each other, and each of the first RF chip and the second RF chip has two pads. Said two pads of the first RF chip and said two pads of the second RF chip are connected to two complementary antennas. The first wiring conducts said two pads of the first RF chip to one of said two complementary antennas. The second wiring conducts said two pads of the second RF chip to the other of said two complementary antennas.

What is claimed is: 
     
       1. A RFID tag comprising:
 a first RF chip and a second RF chip adjacent and connected to each other, wherein each of the first RF chip and the second RF chip has two pads, and said two pads of the first RF chip and said two pads of the second RF chip are connected to two complementary antennas connected, respectively; 
 a first wiring conducting said two pads of the first RF chip to one of said two complementary antennas; 
 a second wiring conducting said two pads of the second RF chip to the other of said two complementary antennas, wherein the first wiring crosses the second wiring in a plan view; and 
 an isolation sticker disposed between the first wiring and the second wiring. 
 
     
     
       2. The RFID tag according to  claim 1 , wherein the first RF chip and the second RF chip generate an omnidirectional radiation pattern. 
     
     
       3. The RFID tag according to  claim 1 , wherein the RFID tag is operated under high frequency (HF) or above. 
     
     
       4. The RFID tag according to  claim 3 , wherein the RFID tag is operated under ultra-high frequency (UHF). 
     
     
       5. The RFID tag according to  claim 1 , wherein the first RF chip and the second RF chip are cut as a whole from a wafer. 
     
     
       6. The RFID tag according to  claim 5 , wherein the first RF chip and the second RF chip are arranged in a row in a first direction and connected to each other, and said two pads of the first RF chip and said two pads of the second RF chip are arranged in a row extending along the first direction in a plan view. 
     
     
       7. The RFID tag according to  claim 5 , wherein the first RF chip and the second RF chip are arranged in a row in a first direction and connected to each other, and said two pads of the first RF chip are arranged in a row extending in a second direction perpendicular to the first direction, and said two pads of the second RF chip are arranged in a row extending in the second direction in a plan view. 
     
     
       8. The RFID tag according to  claim 1 , wherein said two pads of the first RF chip are connected to two ports of one of said two complementary antennas. 
     
     
       9. The RFID tag according to  claim 8 , wherein said two pads of the second RF chip are connected to two ports of the other of said two complementary antennas. 
     
     
       10. A RFID tag comprising:
 a sheet; 
 a first RF chip and a second RF chip adjacent and connected to each other, wherein each of the first RF chip and the second RF chip has two pads; 
 a first wiring conducting said two pads of the first RF chip; 
 a second wiring conducting said two pads of the second RF chip; 
 a first proximity wiring connected to one of two complementary antennas and approximating with the first wiring, wherein the first proximity wiring is arranged to wirelessly conduct said two pads of the first RF chip to one of said two complementary antennas; and 
 a second proximity wiring connected to the other one of said two complementary antennas and approximating the second wiring, wherein the second proximity wiring is arranged to wirelessly conduct said two pads of the second RF chip to the other one of the said two complementary antennas; 
 wherein the first proximity wiring is disposed over a first side of the sheet and extends toward a first corner of the sheet, and the second proximity wiring is disposed over a second side of the sheet opposite to the first side of the sheet and extends toward a second corner of the sheet. 
 
     
     
       11. The RFID tag according to  claim 10 , wherein the first RF chip and the second RF chip generate an omnidirectional radiation pattern. 
     
     
       12. The RFID tag according to  claim 10 , wherein the RFID tag is operated under high frequency (HF) or above. 
     
     
       13. The RFID tag according to  claim 12 , wherein the RFID tag is operated under ultra-high frequency (UHF). 
     
     
       14. The RFID tag according to  claim 10 , wherein the first RF chip and the second RF chip are cut as a whole from a wafer. 
     
     
       15. The RFID tag according to  claim 14 , wherein the first RF chip and the second RF chip are arranged in a row in a first direction and connected to each other, and said two pads of the first RF chip and said two pads of the second RF chip are arranged in a row extending along the first direction in a plan view. 
     
     
       16. The RFID tag according to  claim 14 , wherein the first RF chip and the second RF chip are arranged in a row in a first direction and connected to each other, and said two pads of the first RF chip and said two pads of the second RF chip are each arranged in a row extending along a second direction perpendicular to the first direction. 
     
     
       17. The RFID tag according to  claim 10 , wherein said two pads of the first RF chip are connected to two ports of one of said two complementary antennas. 
     
     
       18. The RFID tag according to  claim 17 , wherein said two pads of the second RF chip are connected to two ports of the other of said two complementary antennas. 
     
     
       19. The RFID tag according to  claim 10 , the first wiring has a first end connecting to one of said two pads of said first RF chip and a second end connecting to the other one of said two pads of said first RF chip. 
     
     
       20. The RFID tag according to  claim 10 , further comprising an isolation sticker disposed between the first proximity wiring and the second proximity wiring.